build-unit-test-docker: update per new format rules

New formatting rules require this change

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: Ieef4c1359d065daa5c636c42cc0618b287285307
diff --git a/scripts/build-unit-test-docker b/scripts/build-unit-test-docker
index 0d60de0..fff4a84 100755
--- a/scripts/build-unit-test-docker
+++ b/scripts/build-unit-test-docker
@@ -594,8 +594,7 @@
 
     @staticmethod
     def build(pkg: str, tag: str, dockerfile: str) -> None:
-        """Build a docker image using the Dockerfile and tagging it with 'tag'.
-        """
+        """Build a docker image using the Dockerfile and tagging it with 'tag'."""
 
         # If we're not forcing builds, check if it already exists and skip.
         if not force_build: